The use of awnings to provide shade for buildings such as homes and commercial establishments and for recreational vehicles is well established. Most commercially available awnings are of the type which are made of a fabric such as canvas and are mounted to the side of a recreational vehicle or wall of a building in such a manner that the awning can be easily raised or lowered. That is, when shade is desired, the awning is lowered to an appropriate position and then can be rolled up during the period when shade is no longer wanted or during periods of bad weather.
In a typical awning installation of the foregoing type, the awning assembly includes two elongated rollers on which the awning fabric is mounted. One of the rollers is mounted to the side of the vehicle or building and an end of the fabric is attached to this roller. The other end of the fabric is attached to a second roller. A pair of braces or supports is attached to the ends of the second roller and then to the side of the vehicle or building to support the awning when it is unrolled and in an extended position to provide shade. Means are provided to raise and lower the awning and such means include a hand operated crank or an electric motor with appropriate gearing.
By their very nature awnings are subjected to great stresses and strains particularly when in the open or extended position. The area of fabric in an awning when in the extended position is large. For example, a typical awning assembly on a recreational vehicle can range up to twenty feet in length and can cover up to about one hundred and sixty square feet in area. Obviously, the awning acts as a sail and even rather mild winds can place great strains on the structure which holds the awning in place while in an extended position. Moreover, since the awning is exposed to the weather, it is desirable that the awning assembly, particularly when it is in a retracted position, be provided with suitable protection.